Brief Report: Discrepancies Between Self-Reported Adherence and a Biomarker of Adherence in Real-World Settings

Abstract

Background: Pre-exposure prophylaxis (PrEP) is only effective in preventing new HIV infections when taken consistently. In clinical practice, asking a patient about their adherence (self-report) is the predominant method of assessing adherence to PrEP. Although inexpensive and noninvasive, self-report is subject to social desirability and recall biases. Several clinical trials demonstrate a discrepancy between self-reported adherence and biomarker-based recent adherence. Less is known about the accuracy of self-report in real-world clinical settings. This brief report addresses this knowledge gap and describes the concordance between self-reported adherence and biomarker-based adherence in real-world clinical settings. Methods: A liquid chromatography–mass spectrometry urine test for tenofovir was developed and used clinically to detect recent nonadherence (no dose in at least 48 hours) for each individual. Two clinics' standard operating procedures recommend utilization of the urine-based adherence test for patients who self-report that they are not struggling with adherence. Those who self-report struggling with adherence receive enhanced adherence support without the need for additional testing. The number of results indicating recent nonadherence from these 2 clinics were analyzed to assess the concordance between self-reported adherence and biomarker-based adherence. Results: Across 2 clinics, 3987 tests were conducted from patients self-reporting as “adherent,” and 564 [14.1%; 95% confidence interval (CI): 13.1% to 15.2%] demonstrated recent nonadherence with the liquid chromatography–mass spectrometry test. At clinic #1 in Florida, 3200 tests were conducted, and 465 (14.5%; 95% CI: 13.3% to 15.8%) demonstrated recent nonadherence. At clinic #2 in Texas, 787 tests were conducted, and 99 (12.6%; 95% CI: 10.4% to 14.9%) demonstrated recent nonadherence. Conclusions: Utilization of biomarker-based adherence monitoring at these 2 clinics resulted in 564 additional patients receiving enhanced adherence support who otherwise would not have been identified as nonadherent to their prescribed PrEP regimen. These findings suggest that objective adherence monitoring can be used clinically to enable providers to identify nonadherent patients and allocate support services accordingly.

How Can We Support the Use of Oral PrEP Among Young Women who Sell Sex? A PrEP Cascade Analysis

“…Data on an offer of PrEP use and current PrEP use were self-reported and therefore subject to error. 20 Almost half the women recruited were lost to follow-up. Our outcomes are subject to bias if PrEP knowledge and use differ by follow-up.…”

Pre-exposure prophylaxis adherence with real-time adherence feedback and partner HIV self-testing: A pilot trial among postpartum women

“…If the result was reactive, participants were referred for confirmatory HIV testing and linkage to HIV care (and immediate PrEP cessation if the participant’s test was reactive). Prior to PrEP adherence counseling, study counsellors requested that women provide a urine sample that was tested using the UrSure/Orasure 22,26 test that provides feedback on the result in 10-15 minutes (control line present=at least one dose in previous 48 hours; control and test lines present=no dose in at least previous 48 hours). Following the results, trained counsellors provided biofeedback adherence counselling based on results from the urine lateral flow assay.…”

“…17 PrEP use in PBFW requires monthly or bi-monthly facility visits with HIV testing throughout the duration of PrEP use, and PrEP consultations are likely the only reason women visit the clinic once postpartum, adding substantial burden. 17 Further, standard PrEP counselling is based on self-reported adherence, which may over-report true drug adherence, 18-22 rather than focusing on addressing barriers to daily PrEP use (and promoting condom use when not adherent) to protect the participant. 22…”

“…17 Further, standard PrEP counselling is based on self-reported adherence, which may over-report true drug adherence, 18-22 rather than focusing on addressing barriers to daily PrEP use (and promoting condom use when not adherent) to protect the participant. 22…”

“…A recently developed immunoassay using urine measures tenofovir (TFV) and is sensitive (96%) and specific (100%) when compared to plasma levels. 22-26 The urine assay shows TFV concentrations if PrEP is taken in the past 48-72 hours and is processed within 10-15 minutes, enabling providers to adapt counselling messages immediately, 22,26 potentially increasing motivation for adherence. We conducted a randomized control pilot trial to test the impact of a combined intervention (HIVST for PrEP users and partners, and real-time adherence biofeedback) on recent PrEP adherence among postpartum women who took PrEP during pregnancy compared to standard of care (SOC).…”